Photo by dcJohn. There are a number of aspects of a theme that can get you banned from Google, and other search engines. Deciphering between safe and unsafe themes is not as easy as just looking for a “Sponsored by…” link.
Through using the methods listed below, you will be able to judge whether or not a theme is safe to use.

1 - Download From The Source

Wordpress themes are often free to download, and sometimes free to distribute. It is not difficult for a site to amass a collection of themes, and add their own spam codes to them. For this reason, if you know the site that the theme originally came from, download it from there.